Truck drive tire

Abstract

A pneumatic truck drive tire comprising a tread, the tread comprising a tread cap, a tread base, and a tread underlayer disposed between the tread cap and the tread base; the tread cap comprising a rubber composition comprising 100 part by weight, per 100 parts by weight of rubber (phr) of a rubber consisting of from 52 to 64 phr of polyisoprene rubber, from 22 to 27 phr of polybutadiene rubber, and from 13 to 21 phr of styrene-butadiene rubber; and 47 to 57 phr of carbon black; wherein the tread cap has a tan delta (100° C., 10% strain, 1 Hz) ranging from 0.13 to 0.16, a storage modulus (100° C., 1% strain, 1 Hz) ranging from 2 to 2.5 MPa, and a tear strength (100° C.) ranging from 19 to 23 N; the undertread comprising a rubber composition comprising 100 phr of a rubber consisting of from 71 to 86 phr of polyisoprene rubber and from 14 to 29 phr of polybutadiene rubber; from 19 to 23 phr of silica; and from 29 to 36 phr of carbon black wherein the undertread has a tan delta (100° C., 10% strain, 1 Hz) ranging from 0.1 to 0.14, a storage modulus (100° C., 1% strain, 1 Hz) ranging from 1.8 to 2.2 MPa, and a tear strength (100° C.) ranging from 28 to 34.

What is claimed is: 
     
       1. A pneumatic truck drive tire comprising a tread, the tread comprising a tread cap, a tread base, and an undertread disposed between the tread cap and the tread base;
 the tread cap comprising a rubber composition comprising: 
 100 part by weight, per 100 parts by weight of rubber (phr) of a rubber consisting of from 52 to 64 phr of polyisoprene rubber, from 22 to 27 phr of cis 1,4-polybutadiene rubber, and from 13 to 21 phr of styrene-butadiene rubber; and 
 47 to 57 phr of carbon black; 
 wherein the tread cap has a tan delta (100° C., 10% strain, 1 Hz) ranging from 0.13 to 0.16, a storage modulus (100° C., 1% strain, 1 Hz) ranging from 2 to 2.5 MPa, and a tear strength (100° C.) ranging from 19 to 23 N; 
 the undertread comprising a rubber composition comprising: 
 100 phr of a rubber consisting of from 71 to 86 phr of polyisoprene rubber and from 14 to 29 phr of cis 1,4-polybutadiene rubber; 
 from 19 to 23 phr of silica; and 
 from 29 to 36 phr of carbon black; 
 wherein the undertread has a tan delta (100° C., 10% strain, 1 Hz) ranging from 0.1 to 0.14, a storage modulus (100° C., 1% strain, 1 Hz) ranging from 1.8 to 2.2 MPa, and a tear strength (100° C.) ranging from 28 to 34 N. 
 
     
     
       2. The pneumatic truck drive tire of  claim 1 , wherein the undertread rubber composition further comprises an organosilicon compounds are of the formula:
   Z-Alk-S n -Alk-Z 
 
       in which Z is selected from the group consisting of 
       
         
           
           
               
               
           
         
       
       where R 1  is an alkyl group of 1 to 4 carbon atoms, cyclohexyl or phenyl; R 2  is alkoxy of 1 to 8 carbon atoms, or cycloalkoxy of 5 to 8 carbon atoms; Alk is a divalent hydrocarbon of 1 to 18 carbon atoms and n is an integer of 2 to 8.